My speaker took out two amps. Whats up? [Archive] - Audio & Video Forums


View Full Version : My speaker took out two amps. Whats up?

11-20-2006, 12:39 PM
This is a long story, so please bear with me.

Last Friday, I had my stereo system on twice. The first listening session lasted about three hours, and there was no sign of impending doom. In fact, the system had been running fine for the whole first week I was at my new address. Anyway, after the first listening session of the day was over, I shut the system down for several hours and went out for awhile.

Upon my return, I fired the stereo back up and put on a live concert DVD (Kissology). Immediately, I noticed that the soudstage was skewed to the left, but I (mistakenly) put it down to the low-fi nature of the concert recording and soldiered on. (The volume wasn't loud.) About twenty minutes in to the show the right channel in my amp went dead, and I could smell burning plastic and solder. In a panic, I ran up to check what was wrong and found that the right side of the chasis was very hot to the touch, and the signal light for that channel was off. I quickly shut the amp down, but it was too late. The right channel was down for the count. Aaarrgghh!!

It was here that I made my second mistake. After several minutes of cursing, I pulled the broken amp from the rack. I figured that it had merely blown some faulty circuit. I then hooked up a backup amp--a Proceed Amp 2--to resume my listening. As soon as I powered it up its right channel went down too. (Thankfully, the Proceed has fuses for each channel, so it may have fared better than my first amp.) It was now clear that the right speaker was causing some problems.

My question is, what could go wrong inside the speaker that would take out an amplifier channel? The reason I ask is that my brother, who has more knowledge than I concerning the ins and outs of electronics, will be visiting me over the holidays. And we will be opening up the speaker in question. What should we be looking for? I've already GENTLY pressed on the woofer and mid drivers and could hear no rubbing. So I think that they are probably OK.

The speaker is a Hales Transcendence 8: a three-way tower that is set up for bi-wiring, and that is how I was using it. I guess I should also point out that when I made my relocation the movers may have been a bit rough or clumsy. (Take your pick.) Because when I opened its box the speaker was misaligned inside, so I have to assume that it may have taken a fall. Still, it ran fine for a week until all of this happened.

Another thing to consider is that it is quite possible that the first amp blew its channel on its own and took out the speaker. Then the speaker took out the second amp.

What a freakin' mess.

Anyway, your comments, personal experiences and helpful hints would be appreciated. Since Hales the company has been out of business for a while now, and no one seems to know where Paul Hales himself can be reached, I'm on my own in repairing the speaker.



11-20-2006, 02:27 PM
Your balance was skewed to the left. I had this happen a couple of times on my computer when using it as a source. This is caused by hacker/s. Since you don't mention a computer I don't know if this applies to you.
Secondly the only time I've had an receiver fry like you discribe was years ago when I had this early model Korg synth hooked to my Fisher. The distortion in the different sound waves was too much for it.So I'm speculating that with your balance skewed and Kissology music that perhaps you were getting to much wave distortion causing receiver to clip frying it as well as your speakers.
Just my .02 cents

Mike Anderson
11-20-2006, 05:03 PM
^^^ Exactly - it was the Kissology that killed your amp.

11-20-2006, 07:14 PM
hmm, maybe a prob with the pre-amp?

check all connections for shorts, probably cause of problem

Dusty Chalk
11-20-2006, 07:36 PM
Short inside the speaker? Take a multimeter to it, and see if you get zero ohms amongst any of the connections.

11-20-2006, 09:13 PM
I agree with Dusty. You may, and probably do, have a shorted speaker.

The first amps right channel may have fried sending DC to your right speaker, frying that, and may have created a short in the speaker which may have blown the fuse in your second amp.

Thank goodness for fuses. They should be used more often, IMO. Lost a good speaker to a fried amp myself. Wish I had fused it.

I've read here that some think fuses alter the sound of a system.

I find that hard to believe, but then again I don't believe you need more than a good 14 guage of speaker wire from Lowes for short runs.

11-21-2006, 12:26 AM
It could be that your preamp has a faulty part and is over driving the input stage of the external power amps.



audio amateur
11-21-2006, 02:11 PM
Stop changing your setup's frequency response!:p (florian) I know it is important to you but still

11-21-2006, 05:04 PM
Thanks for all of your replies. I appreciate all of them.

Florian and Audio_dude, I don't think it's a problem with the preamp. The first amp that blew is actually an integrated unit, and I checked its preamp. It was fine. Now, because I was watching a DVD, I was sending a signal into the integrated from a Rotel prepro. But I know I wasn't overdriving the input on the integrated amp. I've used the Rotel and the integrated together for several years with no problems.

Dusty and yogo, you may be on to something. I assume the short in the speaker would probably be found somewhere in the crossover? If that is the case then I have to assume that it is in the crossover between the midrange and the tweeter. The reason I believe this is because, according to the manual, when you bi-wire these speakers (which I did) the woofers are somehow isolated electrically from the mid/high drivers. And it is from the midrange and treble that we get most of the soundstage information of a recording. And the soundstage was skewed to the left before the first amp died. (Gee, maybe the speaker did cause all of this.)

Also, I think I remember some static type noise coming from the mid/tweeter panel when the first amp went down. So the mid/tweeter crossover is where My brother and I will look first. I just hope the drivers themselves are OK.

Anyway, I like the suggestion regarding adding fuse protection to speakers. How does one do this?

Dusty Chalk
11-21-2006, 08:13 PM
Dusty and yogo, you may be on to something. I assume the short in the speaker would probably be found somewhere in the crossover?(shrug) I don't know.
If that is the case then I have to assume that it is in the crossover between the midrange and the tweeter. The reason I believe this is because, according to the manual, when you bi-wire these speakers (which I did) the woofers are somehow isolated electrically from the mid/high drivers.No, not really (isolated). But sure -- check the uppers first.

Let us know what you find out, please.

11-25-2006, 11:36 AM
stray wire?

11-26-2006, 09:53 AM
meybey, meybey... now this is just an audio mystery!

11-26-2006, 10:31 AM
Ok guys. Here's what my brother and I were able to figure out. None of the drivers are blown. We know this because we were able to get each speaker to emit sound. But as far as the crossover goes, we're at a loss. My brother's multimeter is very basic, so we're limited as to what we can do. Just getting to the crossover was a chore because Paul Hales used some strange bolts to secure the back plate. Also, the inductors are handwrapped and very large. I REALLY hope those aren't the problem.

Anyway, I believe the next step is to find a professional electronics person (or even Paul Hales himself) to look at the crossover. I'm just glad that it appears that I won't have to replace any drivers.

As for my amplifiers, the Proceed Amp 2 is up and running. The blown fuse was the only damage it sustained. The integrated amp is on its way to the manufacturer via UPS for repair, so I shoud get it back in a month or so.

11-27-2006, 04:19 PM
Well, it seems that the Mobile Fidelity integrated did indeed take out the Hales. How do I know this? My brother called up a friend of his who is much more knowledgeable about electronics. And, with the aid of a digital photo I emailed to him and my brother's description of what was happening when he tested various parts of the crossover, we found that the filter caps in the midrange section of the crossover network were blown. In fact, when we looked real close we could see they were cracked.

So, the M.F. integrated blew its output transistors (or whatever you call them) and fried the Hales' filter caps. Then the Hales took out the Proceed's right channel fuse.

As things now stand, one amp is fixed, one amp is on its way for warranty repair, and the Hales crossover is on its way to New Mexico with my brother. His friend knows where to get the parts I need, and he knows how to fix the crossover. Word is it's going to be costly. Paul Hales didn't use cheap parts.

I tried to attach a photo of the crossover network, but I couldn't get the thing to download onto this site.